Spectral imaging is a technique to extract spectral data from an image. State of the art spectral imaging devices contain optical filters positioned on top of an image sensor for filtering and recording incoming light. The filter cavity of each optical filter determines the central wavelength of the spectral band of each optical filter. Some state of the art systems use Fabry-Perot filters which are processed directly on top of the image sensor. Due to intolerances of the fabrication process, there is a misalignment between the actual height of each optical filter cavity and the intended height. This misalignment influences the performance of the spectral imaging device. Apart from fabrication intolerances, changes in environmental conditions such as temperature, pressure or humidity also influence the performance of the spectral imaging device.
There is a need for a spectral imaging device which overcomes at least some of the disadvantages described above.